In May, as HBO’s Chernobyl introduced American viewers to Soviet ineptitude in the face of disaster, United Nations Secretary General António Guterres brought to the world’s attention an embarrassing chapter of the United States’ own nuclear history. Speaking to a group of students during an official visit to the Pacific Islands region, Guterres recounted a meeting he had with Hilda Heine, the president of the Marshall Islands.

Heine, he said, “is very worried because there is a risk of leaking of radioactive materials that are contained in a kind of coffin” in her country.

As several news outlets soon explained, the “coffin” Guterres was talking about is a remnant of nuclear testing the United States conducted on the Marshall Islands after the military annexed the collection of atolls during the Second World War. From 1946 to 1958, the government detonated 67 massive nuclear weapons over the islands—among them, a hydrogen bomb that produced an explosion 1,000 times larger than the bomb dropped on Hiroshima, which was two and a half times larger than scientists had expected. Infamously known as Castle Bravo, the test spread fluffy white radioactive fallout over 7,000 square miles of ocean and sparsely populated islands, where unsuspecting children played in it.

In the late 1970s, the United States attempted to clean up one of the Marshall Islands testing sites. On the Enewetak Atoll, workers scraped the radioactive topsoil and stored it in a pit (the “coffin”), then covered it with a concrete dome 18 inches thick. But the storage was supposed to be only temporary, and after decades of exposure, the dome began to crack. Now, with sea-level rise resulting from climate change expected to submerge the Marshall Islands in coming years, the defective dome is threatening to contaminate that entire area of the Pacific.

Speaking to Australia’s ABC News in 2017, a Marshallese activist referred to the Enewetak dome as “the connection between the nuclear age and the climate change age.” This seems to be the consensus analysis of the situation, and it’s undoubtedly noteworthy—radioactive sites and sea-level rise are a perilous combination that the world is not at all prepared to handle.

Yet there’s more to that equation still. The Castle Bravo miscalculation, the sloppy and inadequate cleanup, even the nuclear tests themselves would have never been issues for climate change to exacerbate if not for the Marshall Islands’ deferential relationship with the United States. It’s a dynamic the country shares with several other current and former territories around the world—Puerto Rico, which Wall Street has kept on life support as a means of extorting profit; the US Virgin Islands, natural disasters on which the federal government has largely disregarded; Guam and the Northern Mariana Islands, at the mercy of the whims of the US military.

And with a climate crisis on the horizon, the hundreds of islands that make up these territories are staring down a deadly and dual-pronged threat: climate change and their own colonial pasts.

The United States was always a cautious kind of colonizer, according to historian Daniel Immerwahr. In his new book, How to Hide an Empire, he recounts the history of what he calls “the Greater United States”—the mostly island territories in the Caribbean and the Pacific that were annexed after the Spanish-American and Second World Wars. Unlike other imperial powers, the United States never aspired to reign over the millions of (brown) people who came with its conquered territories, and it was reluctant to claim them as “part” of the country. (Indeed, as Immerwahr points out, this very magazine encapsulated what was to become the standard racist attitude toward territorial peoples when it pronounced during Alaskan annexation in 1867 that “we do not want” Eskimos as “fellow citizens.”)

Rather, Washington saw the far-flung islands as “pointillist” air and sea ports, and hoped to quietly extract their rubber, fertilizer, and other resources while flaking out on its responsibility to actually govern. It was colonialism in the most mercenary sense: Your land is part of the United States when we need to use it, but don’t even think about calling yourselves Americans.

Under this shadow colonialism, the United States subjected its islander subjects to a wide array of horrors. During the Second World War, the military interned thousands of US nationals in the Philippines and Guam and killed tens of thousands more with its scorched-earth tactics. In Puerto Rico, mainland doctors throughout the 20th century conducted uninformed medical trials on the population, including several by Dr. Cornelius Rhoads, whose genocidal racism prompted him to infect and selectively treat patients as if they were lab animals. And for 60 years, the US military used Vieques, an island off of Puerto Rico, as a bombing range—to the point where the population is still experiencing elevated rates of cancer and arsenic and mercury poisoning. There were also the nuclear tests on the Marshall Islands, from which Marshallese communities are still experiencing cancer, birth defects, and agricultural devastation.

Equally demoralizing is how little the situations on some of these islands have changed over the past century. It’s true that fewer of them are territorially administered by the United States—the Marshalls and the Philippines gained independence, while Hawai’i and the Aleutians (part of Alaska) became states. But even though government-sponsored breakthroughs in synthetics replaced the need for rubber and other colonial materials, and a boom in treaties has supplanted the need for the United States to use conquered territory for military bases, the islands whose colonial status isn’t significantly different from what it was decades ago still have a relationship with the mainland that is primarily extractive, militaristic, or just neglectful.

And with a climate crisis looming, those relationships signal further disaster.

Islands are uniquely vulnerable to the ravages of climate change. And it’s hard, given the US track record (not to mention its outsize carbon footprint), to imagine a constructive and helpful federal response when the worst of its impacts begin to manifest. It would be all too easy for mainland politicians to shrug as rising tides swallow whole islands; as ocean warming and acidification disperse and kill the fish populations on which many island communities rely; as increasingly extreme hurricanes and typhoons pummel islands much harder than continental areas.

In fact, climate-change effects are already being compounded by US negligence and exploitation. Be it radioactive-waste sites from government nuclear tests poisoning rising oceans or precarious power grids designed via federal-tax incentives leaving islands like Puerto Rico susceptible to widespread blackout during storms, the past pillaging of the US’s island territories is making the coming climate crisis even more dire for them.

The federal response to Hurricanes Maria and Irma on Puerto Rico and the US Virgin Islands in 2017 was straight out of Naomi Klein’s The Shock Doctrine—a master class in capitalizing on natural disaster for the sake of redistributing resources inland and upward. After nearly two years, Congress has still only passed minute aid packages; meanwhile, the Virgin Islands have spiraled into literal despair, while vulture capitalists have found, at the intersection of natural destruction and preexisting debt, a sweet spot to suck Puerto Ricans dry. In San Juan, crypto bros have sought to create a tone-deaf, tax-free paradise for their grifts, while authorities working on behalf of Wall Street bondholders have dealt blow after financial blow to grassroots efforts to make Puerto Rico more sustainable, equitable, and climate resilient. Recently, austerity hawks even decided to siphon cash from Puerto Rican households that have installed solar panels in an effort to escape crushing electricity prices and wean their communities off the centralized fossil-fuel grid.

And when island communities do see federal action on climate change, it’s usually tied to a colonialist project. Residents of the United States’ Northern Mariana Islands, for example, got a preview of what a semi-appropriate government response to climate disaster might look like after Super Typhoon Yutu in October 2018, when the Department of Defense moved thousands of tons of storm debris, set up temporary tents for those rendered homeless, and fixed civilian roofs.

Meanwhile, the Navy is in the midst of proposing a contentious plan to appropriate two of the Northern Marianas islands for live-fire exercises as part of a troop buildup on nearby Guam. With no voting representation in Congress, territorial peoples can count on the federal government to help preserve their homes only when it seeks to commandeer them.

Conventional narratives of global history tell us that we live in a postcolonial world. But as author Arundhati Roy recently posed to Boston Review, “Is postcolonial really post-?”Of course it isn’t; it’s just that today’s colonizers wear suits and ties instead of safari outfits (Melania notwithstanding). And as the climate crisis worsens, they will continue to conquer, exploit, profit from, and then wash their hands of the world’s most climate-vulnerable communities—while other expansionist regimes follow suit.

Colonialism was for centuries one of the world’s most powerful scourges. But in this “postcolonial” climate-change era, we are only starting to see its full effects.